Merge #278

278: Add versioning to cache r=lachlansneff a=MarkMcCaskey

resolves #272 

Co-authored-by: Mark <mark@marks-macbook-pro.local>
Co-authored-by: Mark McCaskey <mark@wasmer.io>
Co-authored-by: Lachlan Sneff <lachlan.sneff@gmail.com>

lib/runtime-core/Cargo.toml

@@ -46,3 +46,5 @@ field-offset = "0.1.1"
 [features]
 debug = []
 
+[build-dependencies]
+blake2b_simd = "0.4.1"

lib/runtime-core/build.rs

@@ -0,0 +1,26 @@
+use blake2b_simd::blake2bp;
+use std::{env, fs, io::Write, path::PathBuf};
+
+const WASMER_VERSION: &'static str = env!("CARGO_PKG_VERSION");
+
+fn main() {
+    let mut state = blake2bp::State::new();
+    state.update(WASMER_VERSION.as_bytes());
+
+    let hasher = state.finalize();
+    let hash_string = hasher.to_hex().as_str().to_owned();
+
+    let crate_dir = env::var("OUT_DIR").unwrap();
+    let wasmer_version_hash_file = {
+        let mut path = PathBuf::from(&crate_dir);
+        path.push("wasmer_version_hash.txt");
+        path
+    };
+
+    let mut f_out = fs::File::create(wasmer_version_hash_file)
+        .expect("Could not create file for wasmer hash value");
+
+    f_out
+        .write_all(hash_string.as_bytes())
+        .expect("Could not write to file for wasmer hash value");
+}

lib/runtime-core/src/cache.rs

@@ -207,3 +207,7 @@ pub trait Cache {
     fn load(&self, key: WasmHash) -> Result<Module, Self::LoadError>;
     fn store(&mut self, key: WasmHash, module: Module) -> Result<(), Self::StoreError>;
 }
+
+/// A unique ID generated from the version of Wasmer for use with cache versioning
+pub const WASMER_VERSION_HASH: &'static str =
+    include_str!(concat!(env!("OUT_DIR"), "/wasmer_version_hash.txt"));

lib/runtime/src/cache.rs

@@ -7,7 +7,7 @@ use std::{
 };
 
 use wasmer_runtime_core::cache::Error as CacheError;
-pub use wasmer_runtime_core::cache::{Artifact, Cache, WasmHash};
+pub use wasmer_runtime_core::cache::{Artifact, Cache, WasmHash, WASMER_VERSION_HASH};
 
 /// Representation of a directory that contains compiled wasm artifacts.
 ///
@@ -40,12 +40,17 @@ pub struct FileSystemCache {
 
 impl FileSystemCache {
     /// Construct a new `FileSystemCache` around the specified directory.
+    /// The contents of the cache are stored in sub-versioned directories.
     ///
     /// # Note:
     /// This method is unsafe because there's no way to ensure the artifacts
     /// stored in this cache haven't been corrupted or tampered with.
     pub unsafe fn new<P: Into<PathBuf>>(path: P) -> io::Result<Self> {
-        let path: PathBuf = path.into();
+        let path: PathBuf = {
+            let mut path = path.into();
+            path.push(WASMER_VERSION_HASH);
+            path
+        };
 
         if path.exists() {
             let metadata = path.metadata()?;

src/bin/wasmer.rs

@@ -12,7 +12,7 @@ use structopt::StructOpt;
 use wasmer::webassembly::InstanceABI;
 use wasmer::*;
 use wasmer_emscripten;
-use wasmer_runtime::cache::{Cache as BaseCache, FileSystemCache, WasmHash};
+use wasmer_runtime::cache::{Cache as BaseCache, FileSystemCache, WasmHash, WASMER_VERSION_HASH};
 
 #[derive(Debug, StructOpt)]
 #[structopt(name = "wasmer", about = "Wasm execution runtime.")]
@@ -48,9 +48,11 @@ struct Run {
 
 #[derive(Debug, StructOpt)]
 enum Cache {
+    /// Clear the cache
     #[structopt(name = "clean")]
     Clean,
 
+    /// Display the location of the cache
     #[structopt(name = "dir")]
     Dir,
 }
@@ -72,6 +74,7 @@ fn get_cache_dir() -> PathBuf {
             // We use a temporal directory for saving cache files
             let mut temp_dir = env::temp_dir();
             temp_dir.push("wasmer");
+            temp_dir.push(WASMER_VERSION_HASH);
             temp_dir
         }
     }
@@ -194,8 +197,10 @@ fn main() {
             Cache::Clean => {
                 use std::fs;
                 let cache_dir = get_cache_dir();
-                fs::remove_dir_all(cache_dir.clone()).expect("Can't remove cache dir");
-                fs::create_dir(cache_dir.clone()).expect("Can't create cache dir");
+                if cache_dir.exists() {
+                    fs::remove_dir_all(cache_dir.clone()).expect("Can't remove cache dir");
+                }
+                fs::create_dir_all(cache_dir.clone()).expect("Can't create cache dir");
             }
             Cache::Dir => {
                 println!("{}", get_cache_dir().to_string_lossy());